Diagn��stico espaço-temporal da ocorr��ncia de herbicidas nas ��guas superficiais e sedimentos do Rio Corumbata�� e principais afluentes

Residues of herbicides from sugarcane were monitored in waters and sediments of Corumbata�� River and tributaries. Ametryne, atrazine, simazine, hexazinone, glyphosate, and clomazone were detected in water samples, with negligible levels of ametryne and glyphosate in sediment samples. The area of recharge of the Guarani aquifer presented the highest triazine and clomazone levels. The triazines were detected at higher levels, with atrazine above Brazil's potability and quality standards. Total herbicide levels at some sampling points were 13 times higher than the European Community potability limit. There is no Brazilian standard for ametryne, although the risk is larger due to ametryne's higher toxicity for the aquatic biota.

Vis��es de meio ambiente e suas implica����es pedag��gicas no ensino de qu��mica na escola m��dia

This study was realized with high school Chemistry teachers from the region of and around Florian��polis (SC). It examines the pedagogical implications of these teachers' views on environmental issues, and discusses the possibilities and difficulties of bringing these issues into the Chemistry classroom. The semi-structured interviews were analyzed using Textual Discourse Analysis principles. The dominance of content-based teaching and traditional pedagogical approaches appears to hinder curricular changes. Most subjects pay little heed to environmental issues and their relation to Chemistry, and endorse a view of science as neutral, and the environment as anthropocentric - views far from Green Chemistry principles.

O espaço da pr��tica de ensino e do est��gio curricular nos cursos de forma����o de professores de qu��mica das ies p��blicas paulistas

The literature presents a new understanding of the teaching practice and the supervised internship.Mutual interaction between them is expected one providing subsidies to the other.The present article shows the conceptions prevailing at the S��o Paulo state universities regarding these activities.Students,when interviewed, report difficulties in dealing with classroom situations. It is possible to observe that chemists wish to prepare new chemists deviating from the objectives of a Chemistry course leading to teaching credentials .

Vis��es de ci��ncias de professores de qu��mica: a m��dia e as reflex��es no ambiente escolar no n��vel m��dio de ensino

The present paper discusses the influence of TV and general media on students scientific ideas and the teacher's perception of this influence on students during class time. 17 high-school chemistry teachers with teaching degree, working in state schools, were interviewed. The interviews showed that both, teachers and students, have a positive opinion of science and the scientist. According to their teachers, students' positive view of science is greatly influenced by TV. The developed study shows how important epistemology is in teachers' college formation to offer them a critical perception of science treated in general media.

Energia, meio ambiente e economia: o Brasil no contexto mundial

The cycle of fossil fuels as an energy source for mankind is approaching its end. Finite resources, coupled with greenhouse gas, have led to an increased effort in the search for alternative renewable energy sources. Brazil has a leading position, due to a 46% participation of renewable sources in its primary energy supply, compared to the global average of 12%. The expansion of the renewable sources in Brazil depends on medium and long term planning, and a large volume of investments. The present financial crisis will have major effects in the energy market. Despite a negative initial impact, it is expected that the rearrangement of the financial system will ultimately lead to an expansion in the use of renewable energy sources. Brazil is a tropical country, with the largest biodiversity in our planet and excellent conditions to expand the use of all forms of renewable sources.

Modelos da Qu��mica Qu��ntica no espaço de momento: diferentes representa����es de um mesmo sistema

The conventional approach to simple quantum chemistry models is contrasted with that known as momentum representation, where the wavefunctions are momentum dependent. Since the physical interactions are the same, state energies should not change, and whence the energy differences correlating with the real world as spectral lines or bands. We emphasize that one representation is not more fundamental than the other, and the choice is a matter of mathematical convenience. As spatial localization is rooted in our brains, to think in terms of the momentum present us a great mental challenge that can lead to complementary perspectives of a model.

Tintas anti-incrustantes de terceira gera����o: novos biocidas no ambiente aqu��tico

Antifouling agents have been used on vessels and boats since ancient civilizations. Thus, a brief history on the three generations of antifouling paints was provided in the present review. Additionally, information about physic-chemical properties, environmental levels, toxicology and analytical methods was discussed for the 16 "new" booster biocides used as third-generation antifouling paints. The main problems, limitations and future trends related to this subject were also presented. Finally, actions were suggested in order to appraise the current status of the environmental impact caused by these compounds in South America.

Uso de materiais recicl��veis na determina����o gravim��trica de CO2 no ar ambiente e tratamento dos res��duos de laborat��rio gerados

An alternative system was tested for the determination of CO2 in air using recyclable materials. The results indicate that the proposed system allows for reliable, accurate, robust and efficient collection, comparable to the standard gravimetric method. Laboratory wastes are easily treated using a filtrate that can be discharged into the sewer and solids that can be reused. The proposed system is a simple and low-cost tool that encompasses important aspects of environmental education, which should be part of the education in chemistry of undergraduate students and technicians.

Patenteamento em nanotecnologia no Brasil: desenvolvimento, potencialidades e reflex��es para o meio ambiente e a sa��de humana

Nanotechnology developments continue to be produced at exponential rates for a wide and diverse range of applications. In this paper was done a study of technological forecasting in nanotechnology applied to health, based on information drawn in Brazil from 1991 to 2010. The longitudinal evolutions of the number of patent applications, their topics, and their respective patent families have been evaluated for the total global activity. There were obtained 1352 patent applications in this period. It were analyzed the legal nature of the depositors, the year of deposit, depositors' home countries and processes. It has been a goal subsidizes the policy-makers to adapt and modernize the regulatory framework on nanotechnology and risks involving health as a strategic area in the politics of Science.

APARATO ELETROQU��MICO PARA SISTEMA DE AQUISI����O DE DADOS MULTICANAL COM RESOLU����O ESPA��O-TEMPORAL

Spatiotemporal pattern formation in reaction-transport systems takes place spontaneously when the system is kept far from thermodynamic equilibrium. Targets, reaction fronts, waves, spirals, spots and stripes are some typical examples of selforganized structuring. In electrochemical systems, monitoring spatiotemporal patterns of potential in the solid/liquid interface can be done by the use of equally distributed microprobes located close to the working electrode. However, the physical size of each probe can limit the spatial resolution and alter mass transport properties. In contrast, the direct measurement of discrete electrodes does not suffer from this limitation and allows the accurate manipulation of the spatial coupling through changes in resistors connected to the electric circuit. In this paper, the development of an electrochemical setup for multichannel data acquisition with spatiotemporal resolution is described, especially to monitor low levels of currents usually observed in the electro-oxidation of small organic molecules.

Geoestat��stica como metodologia para estudar a din��mica espaço-temporal de doen��as associadas a Colletotrichum spp. transmitidos por sementes

Objetivou-se no presente trabalho caracterizar o progresso espaço-temporal da severidade da antracnose do feijoeiro comum e da ramulose do algodoeiro por meio da Geoestat��stica. Os experimentos foram conduzidos no campo, durante o per��odo das ��guas, em diferentes ��pocas. Sementes inoculadas pelo m��todo da restri����o h��drica foram semeadas no centro de parcelas experimentais constituindo fonte de in��culo do tipo ponto. Foram realizadas semanalmente seis avalia����es da severidade das doen��as com base em escalas de notas. Pelos modelos de semivariograma isotr��picos esf��ricos e gaussianos ajustados aos dados, verificou-se o padr��o de distribui����o agregado e a depend��ncia espacial de ambos os patossistemas. Com o mapeamento da severidade das doen��as pelo m��todo da krigagem ordin��ria em blocos, verificou-se menor severidade das doen��as nos primeiros est��dios, com aumento gradual ao longo do tempo. A antracnose apresentou forma����o inicial de focos de in��culo secund��rio, al��m do foco com in��culo inicial, que coalesceram com o tempo. A severidade da ramulose diminuiu gradualmente de forma radial e cont��nua do centro da parcela para as extremidades, com maior capacidade de infec����o de plantas vizinhas, quando comparada �� antracnose, possivelmente pela maior agressividade do pat��geno e h��bito de crescimento arbustivo do algodoeiro.

Condi����es de ambiente favor��veis �� germina����o e �� infec����o de Puccinia substriata var. penicillariae em diferentes cultivares de milheto p��rola

A ferrugem do milheto (Pennisetum glaucum), causada por Puccinia substriata var. penicillariae, provoca perdas na produ����o da forragem. Tendo em vista a escassez de informa����es sobre a doen��a no Brasil realizou-se o presente trabalho sobre a sua epidemiologia. Avaliaram-se, em casa-de-vegeta����o, o per��odo latente m��dio, a freq����ncia de infec����o e tamanho das les��es da ferrugem em quatro gen��tipos de milheto: ENA 1, Composto II, BRS 1501 e HKP. In vitro, monitorou-se a germina����o dos uredini��sporos em diferentes temperaturas (10, 15, 20 e 25��C), na presen��a ou n��o de luz. Ap��s isto, avaliou-se o processo de infec����o nos gen��tipos Guerguera, Souna III, BRS 1501 e ENA 1, em c��mara de crescimento, utilizando-se 0, 1, 2, 4, 8 e 12 h de molhamento foliar, na presen��a ou n��o de luz, e em casa-de-vegeta����o, nos gen��tipos ENA 1, Guerguera e Souna III, utilizando-se 3/4, 1, 2, 4, 6 e 8 h de molhamento foliar. O per��odo latente m��dio da ferrugem do milheto variou entre 10 e 12 dias, e os uredini��sporos germinaram em faixa ampla de temperatura, de 10��C a 25��C, na presen��a ou n��o de luz, com germina����o m��xima a 17,5��C no escuro. Nestas condi����es, os primeiros esporos germinaram com menos de 45 min. e atingiram taxa m��xima, 88,2%, em 1,7 h de incuba����o. Infec����es de folhas foram observadas em plantas submetidas a apenas 45 min de molhamento foliar ap��s a inocula����o, por��m, com efeito ben��fico do escuro e do aumento do per��odo de molhamento foliar.

Da ru��na e da conserva����o do mundo: o mundo como espaço discursivo e como discurso espacial

Este trabalho discute o conceito heideggeriano de mundo a partir das no����es de espaço e discurso, tais como elas aparecem em Ser e tempo. Pretendemos assim pensar o mundo como espaço discursivo e como discurso espacial. Isto permitir�� entender por que, como Heidegger diz em A origem da obra de arte, "a ru��na de um mundo �� irrevers��vel". Pensar o mundo como discurso pode tamb��m esclarecer a defini����o grega do homem como animal pol��tico e discursivo, assim como o conceito wittgensteiniano de jogos de linguagem.

A "doen��a dos eruditos" e a triangularidade da ideia de tri��ngulo: uma an��lise do conceito de espaço no tratado de Hume

A an��lise do conceito de espaço no Tratado da natureza humana de Hume o compromete com uma s��rie de teses positivas sobre sua natureza e sobre o conte��do representado por sua ideia: o espaço �� finitamente divis��vel, e sua ideia �� composta de pontos coloridos ou t��teis n��o-extensos, o que o leva a concluir que a ideia de espaço �� ela mesma espacial. Esse conjunto de teses parece comprometer Hume com uma teoria idealista do espaço. Neste artigo, elucido os argumentos de Hume a favor de suas teses positivas e examino seu comprometimento com o idealismo atrav��s de uma caracteriza����o da natureza das proposi����es do Tratado.